Myself as well. The design of this radio is early 50s. I have a similar circuits from the 1960 RCA tube manual that require only A and B(HT) voltages. However this radio had a battery based on destructive examination and markings that provided 7.5V, 1.5V and 90V. So the likely case is "C" voltage or as yet unexamined posibility, a seperate heater supply for the audio output tube. Either way I implmented the power supply to provide the voltages as the battery did only from a switchmode controller and a few NiCds as they are rechargeable. I then package it and wrapped the old printed cardboard around it for realism. I might add the radio is 10" wide, 7" high and about 4" deep and as AM(MW) goes sounds decent. Sound way to go. One of the homebrew designs uses a 45V transformer out of an old printer with a doubler to 110V HT and a seperate one for the 12.6V heaters. Unfamiliar, Elektor is not seen here in USA. Back OT: Anywho valves(tubes) left the computing realm early due to size, cooling and power. The side effects were that physically small circuits for computing were hard to achieve. It also limited speed due to the amount of interconnect wiring required to get signals routed. As to rad hard, there are really two different but related problems for the engineer. One is EMF the other is ionization from high energy particles. EMP as commonly seen is lightning, a high energy pulse that causes a very fast rise and fall time magnetic field and any wires in that field recieve an induced voltages and currents. If the devices are rugged enough they survive. Tubes often qualify there, solidstate devices are often less rugged and are more likely to fail. EMP is also associated with a atomic detonation, the same magnetic effects. The other problem of high energy particles such as Beta and Gamma rays can be from relatively low energy sources and are found in the Van Allen Belt (orbital space), Space itself due to solar activity and around unshielded nuclear materials. The problems associated with radiation is ionization. In semicunductors unwanted ionization will effectively short the device by creating leakage paths in the device (ICs are more susceptable than raw transistors) and also creating small control voltages at active nodes such as the base or gate of a transistor or by depleting or creating a charge where capacitive node are used (DRAMS and microprocessors that use dynamic logic). Device that have high thresholds such as CMOS and tubes are more resistant than TTL and Nmos. It also follows that static logic built with high threshold devices tends to be more resistant. Examples of devices used in EMP risk and environments with high radiation are Tubes, core memory, CMOS micros like 1802, 80C85, 80C188, ARM in CMOS. Core is actually EMP hard and RAD hard due to the closed magnetic nature of each of those thousands of little rings though the surrounding logic has to be handled as a seperate system issue as it's often built with ICs that need protection. The common need for proven RAD (radiation) hard and EMP hard is satelites as they are exposed to radiation and EMP from a variety of sources noteably including the sun. Many Sats have been killed by EMP and/or RAD Allison Kb1gmx